1. Field of the Invention
The present invention relates to a rotary atomization coating device.
2. Related Art
A rotary atomization coating device has been known. By the rotary atomization coating device, a coating, for example of a body of an automobile and the like, is carried out. In the rotary atomization coating device, a high voltage is applied to a rotary atomizing head which is rotating, and a conductive paint (liquid paint) is supplied to the rotating rotary atomizing head to which the high voltage is applied. Thereby, electrified and atomized paint is sprayed from a front end edge of the rotary atomizing head, and an electrostatic coating is performed.
According to the rotary atomizing coating device disclosed in JP-A-07-213991, the paint supplied to the rotary atomizing head through axial holes is led along an inner surface (paint discharging face) of the rotary atomizing head to a discharging end edge as a liquid film. The led paint is subdivided into a number of liquid threads through grooves formed at the discharging end edge to thereby be discharged.
Recently, in order to reduce the number of coating robots, it is required to increase a discharging amount of paint per one rotary atomizing head. If the amount of paint supplied to the rotary atomizing head is increased in the conventional system to meet such requirement, a thickness of the liquid film on a surface of the rotary atomizing head becomes thick, thereby the liquid film flows on the surface of the rotary atomizing head in a state where a sufficient centrifugal force is not provided. In this case, the thick portion of the liquid film flows in a circumferential direction with respect to the rotary atomizing head due to the Coriolis Effect thereby causing the thickness of the liquid film to become thicker. Accordingly, the atomization efficiency is worsened thereby causing a problem in the quality of coating film. To solve such problem, increasing the size of the rotary atomizing head may be considered, but this is not a preferable measure due to a relationship with inner parts and the like of a vehicle or a reduction in the number of revolution caused by an increase in a weight of the rotary atomizing head or the like.